術後25年目に発症した乳癌の食道・胃・十二指腸・大腸転移の1例

Metastatic Involvement of the Esophagus, Stomach, Duodenum and Colon Secondary to Breast, Report of a Case

要旨　患者は72歳の女性で，1973年に右乳癌切除術を受けている．胸部の皮疹を主訴に当院皮膚科を受診，Hb 8.4g/dlと貧血を指摘された．上部消化管内視鏡検査を施行したところ，たこいぼびらん様の小隆起が前庭部から胃体中部にかけて多発しており，胃角部には不整な陥凹性病変が認められた．たこいぼびらん様の隆起および胃角部の生検にて低分化型腺癌が検出された．原発性の胃癌か，乳癌の転移性胃癌かを鑑別する目的で胃前庭部のたこいぼ様病変に対して内視鏡的粘膜切除術を施行した．病理組織標本では，腫瘍細胞は乳癌細胞の形態と非常に類似しており，これらの胃病変は乳癌の転移によるものと考えられた．また，本患者は食道，十二指腸球部，上行結腸から下行結腸にも小隆起が散在しており，生検の結果すべて低分化型腺癌であった．また，皮疹の生検でも低分化型腺癌が検出された．本症例のように術後25年以上経過した例や臨床的に胃以外の消化管の食道・十二指腸・大腸に同時に病変を認めた例は極めてまれであると考えられる．

　A 72-year-old woman visited our hospital because of multiple skin eruptions. She had a history of breast cancer surgically removed 25 years previously.

　Physical and laboratory examinations revealed anemia. Radiological study of the stomach showed irregular-shaped barium flecks surrounded by coarse mucosal folds and multiple polypoid lesions with small barium flecks. These findings were similar to the “bull's eye” sign usually seen in cases of gastric metastasis of malignant melanoma. Endoscopic examination showed multiple flat masses of various sizes, with shallow depressions. Biopsy specimens obtained from these lesions contained adenocarcinoma cells. Further investigations revealed polypoid lesions of the esophagus, duodenum and colon, and biopsy specimens from these organs also contained cancerous cells.

　Histological examination of the cross sections of the mucosectomy specimen of the stomach showed poorly differentiated adenocarcinoma cells in the mucosal layer, and tumor cells were diffusely infiltrating to the submucosal layer. These tumor cells were shown to have characteristics identical to those of breast cancer. These findings clearly demonstrated that the gastric cancer resulted from the previously treated breast cancer.

　Review of the literature indicates gastric metastases from breast cancer are often observed. However, it is extremely rare that metastatic lesions from breast cancer are seen clinically in the esophagus, stomach, duodenum and the colon simultaneously.